Add user defined command line parameters to /? window

With Inno Setup it is possible to add user defined command line parameters. When I use the /?, /HELP command the user defined parameters are not listed there. How can I add my commands with a description to the /?, /HELP window?

Solution

Inno Setup 6.0 supports HelpTextNote message

It's contents will be inserted into the /HELP box.

[Messages]
HelpTextNote=/PLUGIN%nInstalls plugin.

In older versions:

You cannot.

The help text is hard-coded and not customizable in any way. It's not even localized.

It is even displayed before any Pascal Script code (InitializeSetup) is executed, so there's even no room to install some fancy hook to modify the message box on runtime.

See the ShowHelp function in the SetupLdr.dpr.

All you can do is to implement a custom switch (e.g. /usage) and handle it in the InitializeSetup event function.

Or, of course, you can modify Inno Setup source code and re-compile it. It's open source.